import socket


#使用udp连接
s=socket.socket(socket.AF_INET,socket.SOCK_DGRAM)
s.bind(('127.0.0.1',9999))
print('bind udp on 9999...')
while True:
    data,addr=s.recvfrom(1024)
    print('received from %s:%s.'%addr)
    s.sendto(b'hello,%s'%data,addr)
